Blister packs are well known in the art and widely used to package individual items such as different forms of medication including tablets, capsules, and the like. Usually, the item or product is accessed through the rear of the blister pack which is provided with a tear strip.
It is desirable to provide for tamper evident packaging which will give a clear indication when the package has been subject to tampering. However, at the same time, the package must be sufficiently easy for the consumer to open. In addition, the package should provide a degree of child resistance to prevent young children from accessing the contents of the blister pack which, as above mentioned, is frequently medication. Indeed, many countries have laws requiring the use of such packaging. Also, as previously mentioned, the package should be sufficiently easy to open. This becomes particularly important when it is understood that the most frequent users of medication are seniors whose physical strength is frequently limited.
A conventional blister package usually comprises a laminate of a blistered layer having article receiving pockets with a foil backing layer. The foil material is rupturable to release the article. While such a package is inherently tamper evident unless the whole foil layer is replaced, it is not very child resistant. U.S. Pat. No. 4,537,312 to Intini shows one improvement over a conventional blister package. This patent describes claims of package in which such a conventional package is enclosed between an outer front layer and an outer back layer sized larger than the conventional package and sealed to one another around their periphery and through apertures in the laminate. Tabs are provided at the edges of the sealed front and back layers connected to tear strips in the back layer, each of which overlies foil covering a blister pocket. At least the tear strips of the back layer made of a material which, on tearing, will leave a stratum still overlying the foil to thereby reinforce it.
A further improvement is shown in Canadian Patent 1,318,294 to Intini which teaches an arrangement similar to the above and wherein there are provided manually gripable tabs for each tear strip, the tabs being free of the rupturable material.
While the above arrangements have been found to be suitable for providing a child resistant package, the package is not necessarily as senior friendly as it might be. Thus, control of the stratum which overlies the film is not achieved in what may have more or less of the stratum depending upon the inherent nature of the paperboard secured thereto.